Australia brought in new passport rules Thursday allowing citizens to nominate their official gender as male, female or indeterminate, without having to undergo surgery as proof of a sex change.

Canberra had previously required a person whose gender was different from that of their birth to have reassignment surgery before they could change their passport to their preferred sex, and there was no "indeterminate" option.

Attorney-General Robert McClelland said the changes, which come into effect immediately, meant transgendered or intersex people would just need a doctor's letter of support to get a passport in what they considered their true gender.

"Most people take for granted the ability to travel freely and without fear of discrimination," McClelland said. "This measure will extend the same freedoms to sex and gender-diverse Australians."

For those who nominate the indeterminate option, "x" will appear in the gender category in their passport.

Senator Louise Pratt, Australia's first parliamentarian with a transgendered partner - born female but now a man - said the change was a huge step forward.

"There have been very many cases of people being detained at airports by immigration in foreign countries simply because their passports don't reflect what they look like," Pratt told ABC radio.

The move was welcomed by the transgender and intersex community, who called for Australia's state governments to follow suit by allowing birth certificates to also be altered without the prerequisite of surgery.